Control and cutoff mechanism for filling machines



June 17, 1952 P. R. FECHHEIMER CONTROL AND CUTOFF' MECHANISM FOR FILLING MACHINES 2 SHEETSSHEET 1 Filed July 5, 1946 INVENTOR. 1 404 FE'CHHEIME AT'TO R N EYS.

rill/ 4 J1me 1952 P. R. FECHHEIMER 2,600,982

CONTROL AND CUTOFF MECHANISM FOR FILLING MACHINES Filed July 3, 1946 2 SHEETS--SHEET 2 l .9 a2 5 FIG; 6'. INVENTOR. 12 P401. 1?. FECHHE/MEf.

h 6 .94 BY MM Patented June 17, 1952 PATENT UFFICE 2,600,982 contract ANii dirroFF. M EbiI ANisM Fort FILLING MACHINES Paul is Fastener,- Cincinnati; 611a; assig'ii' r' to" The Karl Kiefer Machine company,- Cincinnati, Ohio, a corporation of Ohio Application July 3,1946, serial N6. 681,291 1'5 claims. (0!. 226 97) My invention rnesto; n U jars, cans, bottles; collapsible tubes h d he lil;e, and it has for its principalobject the pr isio'n' of novel means for dontrolli'ngthe new ij the, filling substance duringthe rmal operatipnof the machine and for cutting ofi the" flowjpi filling substance in the event of machine stoppage for any reason. I h H In order that the inventijn may be fully urideistood, I shall describe it in an exi'nplarjeilnbodiment applied to a known filling machine the machine of Patent No 2,-184 ,1'17,' it being understood that the invention beap'plied; to other types of devices; In that patent; to which reference is made for a fuller descriptionof filling machine, I have' desrihed a- IIIQC in w hich the container arefilledduri ie V tinuous travel and in which more than one on tainer may be filled simultaneously} thus greatly increasing the capacity' of the machine; This is accomplished by successively connecting the filling spout for each cont in er to different feed lines for or sources of thefilling material {or pro determined lengths of time, so that each con tainer is filled by increments, the" v'diiime as weir 1 as the rate of iiow of which can be: accurately controlled so that'each container will rece" e the same fill at a desired and cofit'rollahle rate or rates; The machine also ha's Various saiet'y stop features which w'iiibita- N uti ifeiiiafter;

One of the objects of this nv'eh ion istopr ovide" in a combination such as that hereinset forth, a flow-control and cut-oi? me'an very close to the filling spout} so that the new of Inaterial can te'mor accuratelyfs'ta-rt edana tipped in the normar operation of the machine; and with less dripping and drainage than wquld the case were relianceplaced onfthoperation of ports inthe filling head or valves at a distance from the spouts; h V x Another of the objects df injentionis to; provide a mechanism whereby meat or filling material we t. m ately and positively if anything interie' the normal operation ofthemachine,

tiveof the position of th poitsthe irne and irrespective of the operation of or flow control rrfeans located at a" distance" fromthe spouts; Y it These and other objects of the invention which will be set forth hereinafter oi Will-be apparent to one skilled in the art upon r in? these specifications; I accomplish b? that construction and arrangenie'nt'o'fparts'ofwhich I shall now' describe the aforesaid ekeiiiplaryiernloodiinent. Reference is made to the aeedm anying draw: in'gs, wherein: H

Figure 1 is a side'elevatioirdf themachin'e with certain parts cut' awa'y'i 2' filling head and certain parts of my novel mechiim-r. v-

fi ffil-r t s b i izb i i i iqi 05.1 8881114 plary machine taken along the line 3 3 of l lil i-Y .i .t c,

Figure 4 is a plan view oi the filling head. H Figure 5 is a semi-sectional view taken along ll550 1 .1... v

F1gllfe 6 is a sem' sectional view taken along Upon the oecu'rr'ence or any interference with" the ii'c'irin'a'l operation of the machine the entire cam mechanism is fnov'd in such fashion as to permit an v'alves which may be open to close instantly, ail as will be more" fully explained hereinafter;

The exemplary machine w which I have applied the present invention comprises a frame I',' upon whiclrth'various parts aremoiintiit The prime'mover may bea motor 2, provided With'ah exnan'si'bl'e or change" speed pulley 4'; The" motor is slidably mounted on the machine base so that its position" may be controlled by a hand Wh1"'i,'With a resulting change of driving speed. A belt onnectsth'epu'irey 4 with a'pulley 8 on is" connectib'l'e' with the shaft through a clutch mechanism indicated generally at It.

Within" a' housing II; a worm on the shaft 9 eng'ages'" worm Wheel on a" vertical shaft" l2, whibli'eiitendsupwardly through the top of the" frame' of" the machine.

Referring to Figure 5; 'itwill' he seen that" the shaft J2 carries a table l3- arranged to' rotate w'ith:iti: Above the" table there is a star wheel or thelike M'Qalso arranged to rotate with .the shaft. The ,table has-La plurality of platform members I511 located; beneath theflopenings in" filled corita'inefsimaybe: remq ed from the open ra sei e p a iris' 1n the starwheeli and empty containers placed in silicjliijopening'sl the containers passing freely beneath overhea d' pour spouts. At other rn'achine t'ion's" the ca [T serves to hown at ii ht, iii

Figure 5; bringing" the container niouths into a proper relationship with the overhead filling spouts for the filling operation.

The shaft I2 is threaded as to its upper portion, and a lower head member l8 carrying filling spouts I6 is mounted thereon in such a way as to rotate with the shaft. For adjusting the mechanism for containers of different sizes, lower head i8 may be raised and lowered on the shaft [2 by means of a hand wheel 20, a threaded portion of which engages the threads of the shaft.

An upper head member 2| is rotatively mounted with respect to the shaft, rests with a sliding and liquid-tight fit on the lower head 18, and is held from rotation during the rotation of the lower head by means of an arm 22, engaging a post on the machine. The upper head 21 has conduit connections 23 and 24 with two or more feed lines or sources of supply of the filling material. By a construction fully outlined in the said Patent No. 2,184,117, there are cooperating ports in the heads l8 and 2!, functioning in such fashion that the filling spouts ii! are successively connected for predetermined lengths of time with the several conduits 23, 24.

Referring to Figures 1 and 3, a small sprocket 25 and a larger sprocket 26 are rotatively mounted upon the main shaft 9. These are respectively connected by chains 2'! and 28, to large and small sprockets 29 and 30 on a shaft 3|. A clutch member 32 splined on the shaft 9, serves alternatively to connect either of the sprockets 25 or 26, with the shaft 9, or to disconnect both. The clutch member 32 is moved by a fork 33 pivoted on the machine frame as at 34, and provided with an operating handle 35. In this way I provide for driving the shaft 3| from the shaft 9, at two widely divergentspeeds. A variable speed transmission 36 is connected to the shaft 3|, and this combination enables me to control accurately over a very wide range, the speeds of the feeding mechanisms hereinafter described. The variable speed transmission 36 has a control shaft 31 carrying a sprocket 38, which is connected by a chain 39, to a sprocket 40. This sprocket is on a shaft journaled in the machine frame and bearing a hand wheel 4|. The wide range of speed control heretofore mentioned is effected by manipulation of the hand wheel 4|, and the operating lever 35, these being located close together.

The driven shaft of the change speed transmission 36 has a sprocket 42 connected by a chain 43 to a sprocket 44 on a shaft 45 at the side of the machine. The shaft 45 may be on, or may be connected to, the operating shaft of a pump, 46. I have shown a second pump 41, the shaft of which carries a sprocket 48 connected by a chain 49 to another sprocket 50, on the shaft 45. The two pumps 46 and 41, each of which-is capable of delivering the filling material at a volumetric rate proportional to the speed of its shaft, are connected together and driven together from the driven shaft of the change speed mechanism 36. The volumetric performance of each pump relative to the performance of the other, will be determined by the connection between the two pumps, which connection may be chosen or modified to bring about the required relative performance. The combined volumetric performance of both pumps will be determined by the change speed mechanism 36, and thus may be adjusted for containers of different sizes, the proportionate performance of the pumps remaining the same.

Pump 4"! is shown as having avalved inlet means 5 I, while pump 46 has a valved inlet means 52. The outlet port of pump 46 is shown as connected to the head conduit 24 by a conduit 24a including sliding means so that the head mechanism heretofore described can be raised and lowered. Similarly the outlet port of pump 41 is connected to the head inlet means 23 by a conduit 23a having sliding means. My containers may be filled with successive increments of different substances by the means described; and with suitable modification of the construction of the head, the number of increments introduced into each container may be increased by multiplying pumps, drives and conduits. It will be understood that the containers may also be filled with successive increments of the same filling material from different sources; and a valved cross connection 53 between the inlet sides of the pumps enables me to fill containers with successive increments of the same filling material from the same source.

The clutch member [0, splined on the main shaft 9 is operated by a fork control lever 54 pivoted as at 55 on the machine. A heavy tension spring 56 connected between the end of the lever 54 and an abutment 57 on the machine, tends to urge the lever to a position in which the clutch I0 is open. It will be noted that the clutch i0 is a main clutch serving to disconnect the prime mover both from the shaft I2 of the machine table and from the pumps through the variable speed transmission 36.

The lever 54 is connected by a link or rod 58 to a bell crank 59 pivoted on the machine and having an operating handle 80. A member 6| fixed on the rod 58 carries a detent, and a cooperating detent is found on a latch means 62 pivoted to the machine frame at 63, and controlled by a compression spring 64. Thus the clutch member I!) may be thrown into engaged position by the handle 60, and will be held in that position by the latch means just described.

For disengaging the latch and hence permitting the spring 56 to throw out the clutch, I have. shown a solenoid 65, the armature 66 of which is connected with the latch member 62. Energization of the solenoid will cause a movement of the latch against the spring 64, disengaging the detents.

The machine of Patent No. 2,184,117 was provided with certain safety features, operating to energize the solenoid 6|. The worm wheel in the housing II was not affixed directly to the shaft [2, but was rotatively mounted thereon and was provided with a connection means or clutch sufficient to transmit power under ordinary requirements, but arranged to throw itself out under conditions of extraordinary power requirements, as when a jam occurs in the machine. In throwing itself out, the clutch operated a lever (61 in Figure 1) which, by means of a transmission indicated at 68, which does not need to be described in detail, operated a mercury switch 69 (Fi 3).

The containers approach the table l3 and star wheel [4 on a conveyor 10 (Figure 1). Means are provided to deflect the approaching containers into the star wheel, and for removing them from the star wheel to the conveyor, whereupon they are carried away in a continuation of the original direction. At H I provide means of a character to be moved if a container approaches the star wheel incorrectly or fails to seat properly in an opening of the star wheel, together with means which will move if a star wheel opening fails to receive a container. These means through a transmission indicated generally at 12 in Figure 3, operate another mercury switch it. 'Again, the several mechanisms do not require detailed description especially since they are fully described in Patent No. 2,184,117.

The mercury switches 69 and 14 are connected in the circuit of the solenoid 65 so that either switch can produce energization of the solenoid. Additional safety mechanisms may be added to the machine and arranged to produce energization of the solenoid 65 upon the occurrence of undesired conditions during machine operation. Also a special, manually operated, quick-stop button may be provided for the machine and connected into the same circuit. The new mechanism which I shall next describe, is arranged to be operated automatically upon the occurrence of any stoppage of the machine, whether produced manually or by the operation of any type of safety mechanism.

Referring to Figures 4, 5 and 7, in my machine, I connect each filling spout 19 to the rotating lower head i S (and to an outlet port therein) by means of a hollow neck or connecting member '55. Within this neck I provide a positive cut-off valve of any suitable type. The particular exemplary valve is a rotating valve of the perforated barrel type. A member on or connected with the rotating barrel extends through a side arm on the neck 15, and is provided with a crank arm I? for rotating the barrel. The outer end of this crank arm carries a cam following roller 5'3. A spring i9 is wound around the side arm, having one end connected to the side arm and the other end connected to a part of the crank ll. The action of the spring is to urge the crank arm from the valve open position shown in solid lines in Figure 7, to a valve closed position shown in dotted lines in the same figure. Thus, unless definitely actuated, the various valves in connection with the various filling spouts will remain closed.

While in the drawings I have shown filling spouts depending from the valved connecting members, it will be understood that the valves may be located very close to or actually at the tips of the spout means, which is desirable in filling certain materials.

A cam is provided to actuate the valves to open position, mounted on the mechanism next to be described. A central post 80 and two side posts 8i and 52 (Figure 6), are slidably journaled in a cover member 83 spaced from the top plate la of the machine frame. The two outer posts SI and 32, extend through and are also journaled in the top plate la. A bridge or bar 84 connects the three posts below the cover plate 83. Between this bridge and the top plate Id of the machine frame, I provide a toggle connection comprising links or sets of links 85 and 86. The links 85 are pivoted to the bridge and to the links 86 while the. latter are pivoted to a bracket ti, on the top plate of the machine. The cam member 88 is mounted on the upper ends of the posts. It is provided with. clamping means 89 and 98 by which it may be affixed in adjusted position on the posts 8! and 82; but when the clamps are loosened, it is slidable with respect to these posts. The central. post 8i) is threaded as shown and a hand. wheel SM is provided whereby the height of the cam may be adjusted with respect to the position of the head It.

The pivoting of the link or links 33 to the bracket 8'! is accomplished by means of a shaft G2, which is afiixed to the links. The shaft extends through the cover member of the machine and is provided with a rigidly attached arm 93, carrying a weight 94%, or is otherwise biased to ofiset the load of the spout valve springs and the weight of the cam and its mounting. The links and 86 are designed to rest slightly past dead center against any suitable stop (not shown) as indicated in Figure 6, where they maintain the cam in its highest position. This is the position for normal operation of the machine and is also the position at which the cam 88 is adjusted to open the valves. A consideration of Figure 4 will indicate that the cam 88 is so positioned as to open and close the valves at the filling spouts at the proper times during the travel of containers in the machine. Thus the flow of material to the containers is accurately started and accurately stopped, and dripping is minimized.

Without interfering with the normal operation of the machine, I provide means whereby the cam may be bodily lowered to bring all valves to the closed position when the machine stops as aforesaid. This is accomplished through a lowering of the posts 89, BI and 82, by means exerting a definite displacement of the intermediate pivot of the toggle arrangement 85, St, to lower the bridge 84. I engage a link or rod 95 with the intermediate pivot of the toggle, and connect the opposite end of it to a crank arm at (Figure 3), on a stub shaft 91 journaled on the machine frame. This shaft carries another lever 98, which is connected with the clutch operating lever 54, by means of a link 99.

In the particular embodiment described, if anything occurs to energize the solenoid 65, opening the latch 62 and permitting the spring 56 to throw the clutch lever 54 so as to open the clutch i ii, the rod 95 will be actuated to cause the toggle 85, 85, to lower the posts 88, 8| and 82. This carries the cam 88 down far enough so that the previously actuated valves adjacent the filling spouts of my device will close through the action of the springs 19. Thus I obtain automatically a complete stoppage of the fiow of filling material through all filling spouts upon stoppage of the machine for any cause whatever, including both manual operation and the. operation of any safety devices which may be provided. The cessation of the flow of filling material through the filling spouts occurs irrespective of any over-running of parts due to their momentum, irrespective of any continued operation of the pumps, and irrespective of the relative positions of the ports in the heads 58 and 2|.

My invention also makes for accuracy of fill in the following way. When a filling machine is in operation, pressure is built up in the lines between the pumps and the head. When the machine is stopped, the filling material tends to relieve this pressure by continuing to fiow into any containers located under spouts connected to ports which are open for filling. Such containers will be overfilled and may even overfiow. Furthermore, when the machine is again started, the containers immediately succeeding the over-filled containers will be underfilled. My invention operates to prevent the relief of pressure in this fashion, by closing ofi the lines immediately adjacent the filling spout as has been described.

Modifications may be made in my invention without departing from the spirit of it. While I have described my invention in an exemplary embodiment, applied to an exemplary known machine, it will be evident from the teachings above, that it may be applied to other types of machines and to other environments to the same effect. Hence what I claim as new, and desire to secure by Letters Patent is:

1. In a filling machine for containers, a filling spout, means to supply filling material to the filling spout, a valve adjacent said filling spout, cam means for actuating said valve to open it at the start of a filling operation and to close it at the conclusion thereof, means for supporting said cam stationarily in valve operating position during normal operation of the machine and means for bodily moving said cam to an inoperative position upon interruption of the filling operation.

2. In a filling machine for containers, a plurality of filling spouts, means to supply filling material to the filling spouts, a valve adjacent each of said filling spouts, cam means acting automatically to open said valve sequentially at the start of a filling operation and to close them sequentially at the conclusion thereof, and means for supporting said cam means stationarily in valve operating position during norm-a1 operation of the machine, and means for bodily moving said cam means to an inoperative position upon interruption of the filling operation.

3. In a filling machine for containers, a filling spout, means for supplying material to said filling spout, means for moving said containers in a path of travel means for causing said filling spout to travel with a travelling container, a valve adjacent said filling spout and arranged to be actuated by a cam, a cam for actuating said valve to open it at the start of a filling operation and close it at the conclusion thereof, means for supporting said cam stationarily in valve operating position during normal operation of the machine, and means for bodily moving said cam to an inoperative position upon occurrence of stoppage of said machine.

4. In a filling machine for containers, a filling spout, means for supplying material to said filling spout, means for moving said containers in a path of travel means for causing said filling spout to travel with a travelling container, a valve adjacent said filling spout and arranged to be actuated by a cam, a cam for actuating said valve to open it at the start of a filling operation and close it at the conclusion thereof, means for supporting said cam stationarily in valve operating position during normal operation of the machine, and means for bodily moving said cam to an inoperative position upon occurrence of stoppage of said machine, said 'last mentioned means comprising at least one vertical rod, means for supporting said rod in afixed vertical position, and means for moving said rod downwardly upon the occurrence of stoppage in the machine.

5. In a machine for filling containers, a rotating head carrying filling spouts, means for moving containers in conjunction with said head so that a filling spout is positioned with respect to each container to introduce filling material therein, valves adjacent said filling spouts having operating means extending beyond said head, means biasing said operating means to valve closing position, a cam for moving said valve operating means against said biasing means, means for supporting said cam fixedly during normal operations of said machine, and means for moving said cam to an inoperative position to allow said biasing means to close said valves.

6. In a machine for filling containers, means for moving containers, a movable head having filling spouts, means for moving said head so as to move said spouts with respective containers, means for supplying filling material to said spouts, valves adjacent said spouts and having operating means biased to valve closing position, a cam for operating said valves during a portion of the travel of said containers, means for supporting said cam in a fixed operative position, and means for bodily moving said cam to an inoperative position to cause said valves to close.

'7. In a machine for filling containers, means for moving containers, a movable head having filling spouts, means for moving said head so as to move said spouts with respective containers, means for supplying filling material to said spouts, valves adjacent said spouts and having operating means biased to valve closing position, a cam for operating said valves during a portion of the travel of said containers, means for supporting said cam in a fixed operative position, means for bodily moving said cam to an inoperative position to cause said valves to close, and actuating means for said last mentioned means energized upon the occurrence of a stoppage in the machine.

8. In a filling machine for containers, a table upon which containers may be moved through a path of travel, locating means for containers to position them on said table, a rotating head having filling spouts, means to move said head with said table whereby to cause said filling spouts to travel with containers, a fixed head cooperating with the movable head, means in connection with said fixed head to supply filling material thereto, cooperating ports in said fixed head and said movable head to supply filling material to said spouts at given portions of their paths of travel, valves adjacent said filling spouts, a cam for operating said valves in synchronism with the opening and closing of said ports, and means for closing said valves irrespective of the operation of said ports, said last mentioned means comprising means for bodily moving said cam to an operative position.

9. In a filling machine for containers, a rotating table, means for locating containers on said table, a head rotating with said table, filling spouts on said head movable with containers on said table, means for supplying filling material to said filling spouts, valves adjacent said filling spouts, means for operating said valves to open and close them at the start and end of filling operations on respective containers, and means for closing said valves upon stoppage of said machine, said means for operating said valves comprising a cam, and means for holding said cam in a fixed operative position during normal operation of said machine, said means for closing said valves upon stoppage of the machine comprising means for bodily moving said cam.

10. In a filling machine for containers a rotative table, means for locating containers in said table, a rotative filling head, filling spouts on said head, means for rotating said head with said table so as to cause filling spouts to travel with respective containers, a fixed head, means for supplying filling material to said fixed head, cooperating ports in said fixed and movable heads serving to connect said filling spouts with said supply means and disconnect them therefrom, valves adjacent said filling spouts. vertically slidable rods, a cam means supported by said rods for operating said valves in synchronism with the operation of said ports, and means for sliding said rods vertically so as to move said cam for closing said valves irrespective of the operation of said ports.

11. In a filling machine for containers a ro tative table, means for locating containers on said table, a rotative filling head, filling spouts on said head, means for rotating said head with said table so as to cause filling spouts to travel with respective containers, a fixed head, means for supplying filling material to said fixed head, cooperating ports in said fixed and movable heads serving to connect said filling spouts with said supply means and disconnect them therefrom, valves adjacent said filling spouts, vertically slidable rods, a cam means supported by said rods for operating said valves in synchronism with the operation of said ports, and means for sliding said rods vertically so as to move said cam for closing said valves irrespective of the operation of said ports, said machine having a drive and a clutch, means for throwing out said clutch upon the occurrence of a jam in said machine, and a connection between said throw-out means and said means for moving said cam.

12. In a filling machine for containers, a rotative table, means for locating containers on said table, a rotative filling head, filling spouts on said head, means for rotating said head with said table so as to cause filling spouts to travel with respective containers, a fixed head, means for supplying filling material to said fixed head, cooperating ports in said fixed and movable heads serving to connect said filling spouts with said supply means and disconnect them therefrom, valves adjacent said filling spouts, vertically slidable rods, a cam means supported by said rods for operating said valves in synchronism with the operation of said ports, and means for sliding said rods vertically so as to move said cam for closing said valves irrespective of the operation of said ports, said machine having a drive and a clutch, means for throwing out said clutch upon the occurrence of a jam in said machine, and a connection between said throw-out means and said means for moving said cam, said fixed head having connections with a plurality of feeding means for filling material, said feeding means including individual pumps, the action of said ports in said fixed and movable heads being such as to connect said filling spouts successively with said several feeding means, drive means interconnecting said pumps in a given ratio, and drive means connecting the interconnected pumps with said machine drive means so as to be afiected by said clutch.

13. In a filling machine for containers a rotative table, means for locating containers on said table, a rotative filling head, filling spouts on said head, means for rotating said head with said table so as to cause filling spouts to travel with respective containers, a fixed head, means forsupplying filling material to said fixed head, cooperating ports in said fixed and movable heads serving to connect said filling spouts w1th 10 said supply means and disconnect them therefrom, valves adjacent said filling spouts, vertically slidable rods, a cam means supported by said rods for operating said valves in synchronism with the operation of said ports, and means for sliding said rods vertically so as to move said cam for closing said valves irrespective of the operation of said ports, said machine having a drive and a clutch, means for throwing out said clutch upon the occurrence of a jam in said machine, and a connection between said throw-out means and said means for moving said cam, said fixed head having connections with a plurality of feeding means for filling material, said feeding means including individual pumps, the action of said ports in said fixed and movable heads being such as to connect said filling spouts successively with said several feed-' ing means, drive means interconnecting said pumps in a given ratio, and drive means connecting the interconnected pumps with said machine drive means so as to be aiTected by said clutch, and further means for throwing out said clutch upon the occurrence of a misplacement of containers whereby also to actuate said cam.

14. In a device of the character described a filling head having valved filling spouts, resilient means biasing the operating elements of the valves to out off position, a cam means for engaging and operating the operating elements of the valves, a movable support for said cam means comprising at least one vertically slidable rod, toggle means connecting said rod with a support, resiliently acting means in connection with the toggle means for counteracting the weight of the cam and its support and the load of the resilient valve biasing means, and means in connection with said toggle means for moving said cam to an inoperative position as respects all of said valves.

15. In a filling machine for containers, means for moving containers in a path, a movable head having filling spouts, means for moving said head to cause said filling spouts to travel with respective ones of said containers, a fixed head cooperating with the movable head, means for supplying filling material to said fixed head through different feeding means, cooperating ports in said fixed head and said movable head operating to connect said filling spouts in sequence with different ones of said feeding means and to interrupt the fiow of the filling material, valves adjacent said filling spouts, cam means operating said valves in synchronism with the operation of said ports, and means for holding said cam means in a fixed operative position during normal operation of said machine, and means for bodily moving said cam to an inoperative position upon interruption of the filling operation.

PAUL R. FECHHEIMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 988,657 Pfaff et al. Apr. 4, 1911 1,775,293 Pfening et a]. Sept. 9, 1930 2,145,765 Huntley et al June 31, 1939 2,202,033 Stewart et al May 28, 1940 2,362,793 Ayars Nov. 14, 1944 2,389,268 McKinnis Nov. 20, 1945 

